反应 #89688

反应方程式

phenylselenyl chloride

2-allylcyclopentanone

lithium bis(tri-methylsilyl)amide tetrahydrofuran

→

2-allyl-5-(phenylselanyl)cyclopentanone

收率 71.0%

溶剂

tetrahydrofuran

tetrahydrofuran

反应条件

后处理

1. 1
   其他temperature below −55° C
2. 2
   workup.ADDITIONOnce the addition
3. 3
   workup.STIRRINGthe mixture stirred at −60 to −70° C. for 30 min
4. 4
   温度to warm to 0° C
5. 5
   其他The reaction was quenched by addition of the solution to a rapidly stirred mixture of ethyl acetate (500 mL) and 5% aqueous citric acid (200 mL)
6. 6
   其他the organic layer was separated
7. 7
   萃取The aqueous solution was extracted with ethyl acetate (2×100 mL)
8. 8
   洗涤the combined organic solution was washed with saturated aqueous sodium chloride (200 mL)
9. 9
   干燥dried (MgSO4)
10. 10
    浓缩concentrated in vacuo
11. 11
    workup.DISSOLUTIONThe residue was dissolved in heptane
12. 12
    洗涤eluted with 2:1 heptane/dichloromethane

实验过程

While under a nitrogen, a solution of 2-allylcyclopentanone (12.4 g, 100 mmol) in anhydrous tetrahydrofuran (100 mL) was cooled to −70° C. and treated with 1 N lithium bis(tri-methylsilyl)amide/tetrahydrofuran (200 mL, 200 mmol) at a rate to keep pot temperature below −55° C. Once the addition was complete, the mixture was stirred at −60 to −70° C. for one additional hour. A second solution of phenylselenyl chloride (19.5 g, 102 mmol) in anhydrous tetrahydrofuran (50 mL) was added dropwise and the mixture stirred at −60 to −70° C. for 30 min, then allowed to warm to 0° C. The reaction was quenched by addition of the solution to a rapidly stirred mixture of ethyl acetate (500 mL) and 5% aqueous citric acid (200 mL), and the organic layer was separated. The aqueous solution was extracted with ethyl acetate (2×100 mL) and the combined organic solution was washed with saturated aqueous sodium chloride (200 mL), dried (MgSO4), and concentrated in vacuo. The residue was dissolved in heptane and loaded onto a silica gel column (˜600 cc) and eluted with 2:1 heptane/dichloromethane, then with 1:1 heptane/dichloromethane to afford 2-allyl-5-(phenylselanyl)cyclopentanone (19.7 g, 71%) as a pale yellow oil. NMR (CDCl3): δ 7.40-7.50 (m, 2 H), 7.05-7.25 (m, 3 H), 5.50-5.70 (m, 1 H), 4.80-4.95 (m, 2 H), 3.45-3.75 (m, 1 H), 2.30-2.50 (m, 1 H), 1.80-2.25 (m, 5 H), 1.50-1.75 (m, 1 H). MS (M+1): 279.1/280.9 (for 2 major isotopes of Se).

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